Film is a medium used to record images, a consumable in photography. Packaged film in a box is also known as a roll of film.

Commonly, the film comprises a transparent thin film base coated on one side with a gelatin emulsion containing tiny photosensitive silver halide crystals. The size and characteristics of these silver halide crystals determine the film's sensitivity, contrast, and resolution.

When exposed to light, the silver ions in the film's silver halide gradually reduce to metallic silver, darkening the emulsion. However, this process is too slow and incomplete for practical use. Instead, brief exposures through the lens create extremely subtle chemical changes in proportion to the light absorbed by each crystal. This forms an invisible latent image in the emulsion, later developed chemically to create a visible image.

Black and white film typically contains a single light-sensitive layer. During development, exposed silver halide crystals are reduced to metallic silver, blocking light and appearing as black areas in negative film. Color film comprises at least three light-sensitive layers combined with different combinations of sensitizing dyes. As with black and white film, silver ions are reduced to metallic silver during development.

However, byproducts of the development process combine with color couplers present in the film or developer solution, forming color dyes. As the production of these byproducts is proportional to the exposure and development, the resulting color dyes are also proportional to the exposure and development.

After development, the metallic silver is converted back to silver halide during the bleaching step and removed during fixing. This leaves behind the formed color dyes, which together constitute the visible color image.

Compared to the fierce competition in streaming and cinema, the battle between digital movie technology (hereinafter referred to as "digital") and film has long lost its suspense.

Since the historic commercial digital screening debut of "Star Wars: Episode - The Phantom Menace" in 1999, digital cinema has been increasingly adopted by more filmmakers, prompting cinemas to transition to digital screens.

Two decades later, digital has overwhelmingly dominated, drastically reducing film production, and film giant Kodak has fallen into obscurity akin to "Nokia." We've entered an era where digital reigns supreme in movies. If not for the staunch resistance led by directors like Nolan and Tarantino, the world might have witnessed the end of film production.

Interestingly, film is more enduring than digital.

Digital Indeed offers convenient management and storage on computers or hard drives.

However, both computers and hard drives have limited lifespans, often not exceeding ten years, and there's no guarantee against sudden electronic failures causing permanent data loss. This necessitates vigilant human management of the stored cinematic treasures.

Film might seem fragile, yet with proper preservation, its lifespan can extend to over a hundred years. Creating a copy at some point ensures its preservation. "Metropolis," filmed in 1927, has undergone nearly a century of weathering but still receives restoration and viewing.

Digital movies undoubtedly hold absolute advantages and better align with modern filmmaking methodologies.

However, the ubiquity of something doesn't inherently make it superior.

Just as the handcrafted essence of Ferrari persists despite the proliferation of cheaper car brands, film, in its evolution through various technological means, is an inevitably replaceable medium. Yet, the film remains a memory that cannot be entirely replaced. Perhaps, film restorers are diligently maintaining this memory.

They carry forward the dreams and memories of predecessors, safeguarding this "artifact" for future study. As a worker in a film scanning room once said, "Film, it's almost gone, but its importance lies in its endurance. Once it stays, it becomes something for future generations to study."

Perhaps, in the not-so-distant future, the film might indeed become an exhibit waiting for future generations to research. Yet, it carries with it not only the history and stories of the film era but also the time accumulated by those who restore the film and their unwavering dedication and reverence from start to finish.